Recording apparatus



June 2l, 1932. H. J. MCCREARY 1,864,363

RECORDING APPARATUS Filed April 2l. 1930 s wmwllfllr-w/gm ir 33 i i Fig.5.

Inventor: Harold J. lUIcC'r'eclr'H b5 M14/MW HLS Attorneg.

Patented June 21, v 1932 UNITED STATES PATENT OFFICE ELEcTRIc com- PANY,A CORPORATION 0F NEWYORVK RECORDING APPARATUS Application led April 21,

My invention relates to apparatus for photographically recordingelectrical variations. More particularly it ,relates to apparatus formaking a. photographic record of sound waves on a moving sensitivemember. It-is the objective of my invention to provide improvedapparatus for this purpose which among other advantages shall be freeofinertia effects and which is thus adapted for the 'recording of highfrequency variations.A In accordance with my invention I cause a narrowbeam of electrons or cathode rays to be ejected from the evacuatedenvelope in which they are produced and to be modulated by thevariations to be recorded. Through Said cathode rays l pass a memberwhich is sensitive'thercto, such for example as a photographic film.

AMy invention will be better understood from the following descriptiontakenl in connection with the accompanying drawing, and its scope willbepointed out in the appended claims.

Referring to` the drawing, Fig. 1 illustrates one embodiment of myinvention adapted for making a. photographic sound record ofthe variableintensity type on a film of the motion picture type; Fig. 2 shows adetail thereof drawn to a larger scale including the Lenard windowconstruction used and a portion of the sensitive film; Fig. 3 shows afragment ofV a motion picture film having at one side thereof a soundrecord made by the apparatus illustrated in Fig. 1; Fig. 4 is similar toFig. 1 but illustrates a modified form by means of which a sound recordof the variable width type may be made; and Fig. 5 shows a fragment of amotion picture film having thereon a sound record made by this modifiedform of apparatus.

In the form of apparatus illustrated by Fig. .1, I have shown the soundpick-up device l, such for example as a condenser microphone, connectedthrough the amplifier 2 to the cathode ray tube 3 which tube isconstructed to eject electrons or cathode rays in -a narrow band throughwhich passes the moving film 4, the intensity of the rays being variedin accordance with the sound waves received by the vpick-up device. Thetube 3' is 1930. serial no. 446,005.

shown having the hot cathode 6 which'is arranged in the cup-shapedmember 7 and to which energy for heating the cathode is supplied by thebattery 8 under the control of" the rheostat -9. The anode comprises themetal tube 10 which is sealed in the wall of the tube 3 and extendsexternally thereof. Suitable means, shown for example as the battery 11,is connected to the anode tube 10 and to the cathode for raising thetube to the proper positive potential to cause the ejection of thecathode rays. The control of the intensity of the ejected rays may beeffected in y various ways. In the drawing I have shown it secured bythe use of the grid 12'which by connection to the amplifier has itspotential varied in the well known manner in accordance with theamplified current variations received from the pick-up device. The outerend head or plate 13 of the anode tubelO is provided with a very narrowopening or slit 14 whose length equals the width of the desired soundtrack on the film and whose width may, for example, be of the order ofone onethousandth of an inch. The slit is shown covered by a piece ofvery thin metal foil 15, such for example as aluminum foil, which issecured tothe outer face of the end plate 13 as for example bysoldering. vThrou h the Lenard windowv thus formed, the catho rays areejected from the evacuated generetting tube and are caused to engageAthe moving sensitive lm 4. This film preferably runs as close aspossible tothe foil 15 and may be sup ported and moved in any suitablemanner. Asillustrated in Fig. 1,the film is shown as of the motionpicture type having sprocket tooth holes 16 and as supported on theroller orvdrum 17 mounted on the shaft 18. The` film should be movedatthe point ofl engagement with the rays with a uniform movement forwhich purpose the film may be driven at that point by the drum or may bedrawn over the drum by other suitable mechanism. In Fig. 3 I haverepresented the film 4 drawn to a larger scale and as showing Ithedeveloped variable density sound record 19 thereon arranged adjacent onerow of sprocket holes. While I have described the filmas being o f themotion picture type it need not necessar1- Aas . which is transverse to'in Fig. 1 and may 4nism in the case of combined sound and picturerecords. Moreover, where theiilm 4 is to be used only for therecordingof sound it may have an emulsion which while highlyv sensitiveto cathode rays is not necessarily sensitive to any great degree -toordinary light rays. i

The modified form of my invention illustrated by Fig. 4 is constructedfor making a sound record of the variable width type. The cathode raytube 25 in this case is shown somewhat longer than the correspondingtube 3 of Fig. l but vmay be similai` thereto in the construction of thecathode, the anode and the Lenard window. Within the tube 25 and next tothe cathode cup 7 is the centrally apertured plate 26 which by theconductor 27, sealed in the tube wall, connects with the cathode heatingcircuit. Beyond the plate 26 and in alinement with the opening thereinis the tube 28 which as shown is supported by the conductor 29 sealed inthe tube wall. Between the tube 28 and the anode 10, I provide thespaced plates 30 which are supported opposite each other by the sealedin conductors 31. The cathode heating circuit is similar to that shownin Fig. l. The source l1 of anode potential in this case connects notonly with the anode l() but with the tube 28. Plates 30 connect throughtheir supports 31 4and suitable conductors with the output side of theamplifier 2 which as in Fig. 1 amplifies the current impulses receivedfrom a pickup device l. Grid leaks 32 are shown between plates 30 andbattery 11. Film 33 upon which the variable width record is made isshown supported on the drum 17 as be moved uniformly past the rays inthe manner already described. In this form of my invention it will benoted that variations in potential applied tothe plates 30 in accordancewith the sound waves actuating the pick-up device cause a variabledeflection in the pencll of cathode rays reachvingthe Lenard windowwhich deflection takes direction of the window slit the direction ofmovement of the film. The pencil of rays preferably is so adjustedrelative to the slit that as it is vibrated by the varying potentialapplied to the plates 30 more or less of the rays find passage throughthe slit to the film. The developed variable width record thereby madeon the film33 is represented atl 34 in Fig. 5. v

In illustrating my invention I have not attempted to show all of theparts thereof in their proper proportions. In the interest of simplicityand clearness I have purposely omitted certain obviously essentialfeatures place in the of apparatus of thischaracter, such for eX-modifications may for the film to properly protect it not onlyfrom'light but from stray cathode and X-rays which may escape from thetube.

I have chosen the particular embodiments described above as illustrativeof'my invention and .it will be apparent that various other e madewithout departing from the spirit and scope of my invention whichmodifications I aim to cover by the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. Apparatus for making Aa photographic record of electrical variationson a moving light sensitive member comprising a cathode ray tubeconstructed to produce a pencil of cathode rays and having an evacuatedenvelope provided with a window forming a slit through which the cathoderays are e]ect ed from the tube, said tube having electrodes thereinarranged to cause a deflection of the pencil of rays in the direction ofthe slit in accordance with said electrical variations.

2. Apparatus for making a photographic sound record comprising a cathoderay tube having means for producing a pencil of cathode rays and havingan evacuated envelope provided with a metal window forming a slitthrough which the cathode rays are ejected from the tube, means forsupporting a light sensitive member for movement transversely of saidslit, a plurality of electrostatic plates in said tube arranged atopposite sides of the pencil of rays and separated in a directionparallel to said slit and means for ap plying to said plates a potentialdifference which varies in accordance with the sound waves to berecorded.

In witness whereof, I have hereunto set my hand this 15th day of April,1930.

y HAROLD J; MCCREARY.

